Transmission management apparatus

ABSTRACT

A transmission management apparatus manages transmission states of a plurality of transmission terminals including a first transmission terminal and a second transmission terminal. The apparatus includes a terminal management table storage unit configured to store therein a terminal management table in which terminal information including an identifier and an identification name of each transmission terminal is managed; a receiving unit configured to receive a terminal information request signal from the first transmission terminal, the terminal information request signal indicating a request for information for identifying the second transmission terminal, the first and second transmission terminals being in transmission therebetween; a terminal state acquisition unit configured to acquire the information for identifying the second transmission terminal from the terminal management table in response to the terminal information request signal; and a transmitting unit configured to transmit the information acquired by the terminal state acquisition unit to the first transmission terminal.

This application is a divisional Application of U.S. application Ser.No. 13/989,665, filed May 24, 2013, which is a National Stageapplication of PCT/JP2012/55011, filed Feb. 22, 2012, and claimspriority to Japanese Priority Application No. 2011-236251 filed Oct. 27,2011, and Japanese Priority Application No. 2011-042365 filed Feb. 28,2011. The entire contents of the above-identified applications areincorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a transmission management apparatus,for example, to a transmission management apparatus that managestransmission states of transmission terminals used in a remoteconference system with which a remote conference is held through anetwork.

BACKGROUND ART

Remote conference systems realize situations similar to actualconferences as follows. Images and sounds are collected by imagingattendees and collecting utterances of the attendees in conference roomswhere remote conferences are held. The collected images and sounds areconverted into digital data and transmitted by transmission terminals onone side to other transmission terminals on the other parties' side. Theimages are displayed on displays such as video screens and the soundsare output from speakers in conference rooms on the other parties' side.

In an example of such remote conference systems, a remote conference canbe realized among a plurality of sites by a relaying apparatus that iscoupled to all of the transmission terminals attending the conferenceand controls delivery of image data and sound data to each transmissionterminal.

Generally, in a remote conference held among sites, a display screen ofthe transmission terminal is divided into the number of transmissionterminals attending the conference and images transmitted from othertransmission terminals are displayed in the divided areas on the displayscreen so as to know who is attending the conference through othertransmission terminals during the conference (e.g., refer to JapanesePatent No. 3308563).

Such a conventional technique, however, has a problem in that users whouse the respective transmission terminals cannot grasp whichtransmission terminal is attending the conference when the number oftransmission terminals attending the conference increases because thedivision number of the display screen is increased and thus a displayarea for displaying an image transmitted from each transmission terminalis reduced.

Therefore, there is a need for a transmission management apparatus thatenables users who use respective transmission terminals to grasp whichtransmission terminal is attending a conference regardless of the numberof transmission terminals attending the conference.

DISCLOSURE OF INVENTION

It is an object of the present invention to at least partially solve theproblems in the conventional technology.

According to an embodiment, there is provided a transmission managementapparatus for managing transmission states of a plurality oftransmission terminals including a first transmission terminal and asecond transmission terminal. The transmission management apparatusincludes a terminal management table storage unit configured to storetherein a terminal management table in which terminal informationincluding an identifier and an identification name of each of thetransmission terminals is managed; a receiving unit configured toreceive a terminal information request signal from the firsttransmission terminal, the terminal information request signalindicating a request for information for identifying the secondtransmission terminal, the first transmission terminal and the secondtransmission terminal being in transmission therebetween; a terminalstate acquisition unit configured to acquire the information foridentifying the second transmission terminal from the terminalmanagement table in response to the terminal information request signal;and a transmitting unit configured to transmit the information acquiredby the terminal state acquisition unit to the first transmissionterminal.

According to another embodiment, there is provided a transmissionterminal that includes a transmitting unit configured to transmit aterminal information request signal to a transmission managementapparatus for managing transmission states of a plurality oftransmission terminals through a network, the terminal informationrequest signal indicating a request for information for identifying atleast one of the transmission terminals, the transmission terminal andthe at least one of the transmission terminals being in transmissiontherebetween; a receiving unit configured to receive the informationthat is transmitted from the transmission management apparatus inresponse to the terminal information request signal; and a displaycontrol unit configured to cause a display unit to display theinformation received by the receiving unit.

According to still another embodiment, there is provided a transmissionsystem that includes a plurality of transmission terminals eachaccording to the transmission terminal according to the aboveembodiment; and the transmission management apparatus according to theabove embodiment.

According to still another embodiment, there is provided a transmissionmanagement method for managing transmission states of a plurality oftransmission terminals including a first transmission terminal and asecond transmission terminal using a transmission management apparatus.The transmission management method includes receiving a terminalinformation request signal from the first transmission terminal, theterminal information request signal indicating a request for informationfor identifying the second transmission terminal, the first transmissionterminal and the second transmission terminal being in transmissiontherebetween; acquiring the information for identifying the secondtransmission terminal from a terminal management table in which terminalinformation including an identifier and an identification name of eachof the transmission terminals is managed, in response to the terminalinformation request signal, the terminal management table being storedin a recording medium; and transmitting the acquired information to thefirst transmission terminal.

According to still another embodiment, there is provided a transmissionterminal control method using a transmission terminal. The transmissionterminal control method includes transmitting a terminal informationrequest signal to a transmission management apparatus for managingtransmission states of a plurality of transmission terminals through anetwork, the terminal information request signal indicating a requestfor information for identifying at least one of the transmissionterminals, the transmission terminal and the at least one of thetransmission terminals being in transmission therebetween; receiving theinformation that is transmitted from the transmission managementapparatus in response to the terminal information request signal; andcausing a display unit to display the received information.

According to still another embodiment, there is provided a computerprogram product that includes a non-transitory computer readable mediumincluding programmed instructions, wherein the instructions cause acomputer to execute any one of the method according to the aboveembodiment.

The above and other objects, features, advantages and technical andindustrial significance of this invention will be better understood byreading the following detailed description of presently preferredembodiments of the invention, when considered in connection with theaccompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic illustrating a structure of a transmission system;

FIG. 2 is a conceptual view illustrating a state of transmitting andreceiving of image data, sound data, and various types of managementinformation in the transmission system;

FIG. 3 illustrates image quality of the image data;

FIG. 4 is an external view of a transmission terminal;

FIG. 5 is a schematic illustrating a hardware structure of thetransmission terminal;

FIG. 6 is a schematic illustrating a hardware structure of atransmission management apparatus, a relaying apparatus, or a programsupply apparatus;

FIG. 7 is a functional block diagram of the transmission terminal andthe transmission management system;

FIG. 8 is a conceptual view of a terminal authentication managementtable;

FIG. 9 is a conceptual view of a terminal management table;

FIG. 10 is a conceptual view of a destination list management table;

FIG. 11 is a sequence diagram illustrating preparatory stage operationof the transmission system;

FIG. 12 is a sequence diagram illustrating conference attendanceoperation of the transmission system;

FIG. 13 is a sequence diagram illustrating data transmission operationof the transmission system;

FIG. 14 is a conceptual view illustrating a display screen in anall-image display mode;

FIG. 15 is a conceptual view illustrating a display screen in aninformation display mode; and

FIG. 16 is a sequence diagram illustrating terminal information displayoperation of the transmission system.

BEST MODE FOR CARRYING OUT THE INVENTION

An embodiment of the present invention will be described below withreference to the accompanying drawings.

<<Overall Structure of Embodiment>>

FIG. 1 is a schematic of a transmission system 1 according to theembodiment. FIG. 2 is a conceptual view illustrating a state oftransmitting and receiving of image data, sound data, and various typesof management information in the transmission system 1. FIG. 3illustrates image quality of the image data.

The transmission system includes a data supply system in which contentdata is transmitted from a transmission terminal to a plurality oftransmission terminals through a transmission management apparatus inone direction and a communication system in which information andfeelings, for example, are mutually transmitted among the transmissionterminals through the transmission management apparatus. Thecommunication system is a system for transmitting information andfeelings mutually between a plurality of communication terminals(corresponding to the “transmission terminals”) through a communicationmanagement apparatus (corresponding to the “transmission managementapparatus”). Examples of the communication system include a videoconference system and a video telephone system.

In the embodiment, the transmission system, the transmission managementapparatus, and the transmission terminal are described on the assumptionof the video conference system as an example of the communicationsystem, a video conference management apparatus as an example of thecommunication management apparatus, and a video conference terminal asan example of the communication terminal. That is, the transmissionterminal and the transmission management apparatus are applicable to notonly the video conference system but also the communication system or adata transmission system.

As illustrated in FIG. 1, the transmission system 1 includes a pluralityof transmission terminals 10 aa, 10 ab, . . . , displays 120 aa, 120 ab,. . . , for the respective transmission terminals 10 aa, 10 ab, . . . ,a relaying apparatus 30, a transmission management apparatus 50, and aprogram supply apparatus 90. The transmission terminals 10 aa, 10 ab, .. . , perform transmission by transmitting and receiving content data,such as image data and sound data.

In the following descriptions, an arbitrary transmission terminal amongthe transmission terminals 10 aa, 10 ab, . . . , is expressed as a“transmission terminal 10”, and an arbitrary display among the displays120 aa, 120 ab, . . . , is expressed as a “display 120”. In addition,one of the transmission terminals 10 that requests a start of a videoconference as a request source is expressed as a “request sourceterminal” and another transmission terminal 10 that is a destination ofthe request is expressed as a “destination terminal”.

As illustrated in FIG. 2, in the transmission system 1, a managementinformation session SEI for transmitting and receiving various types ofmanagement information is established between the request sourceterminal and the destination terminal through the transmissionmanagement apparatus 50.

Between the transmission terminals 10 with the management informationsession SEI established, four sessions are established for transmittingand receiving four pieces of high resolution image data, mediumresolution image data, low resolution image data, and sound data throughthe relaying apparatus 30. In the embodiment, the four sessions arecollectively expressed as an “image/sound data session SED”.

The image data in the embodiment is scalably encoded. For example, imagedata in the embodiment includes low resolution image data that iscomposed of 320 pixels horizontally and 180 pixels vertically asillustrated in (a) of FIG. 3 and serves as a base image, mediumresolution image data composed of 640 pixels horizontally and 360 pixelsvertically as illustrated in (b) of FIG. 3, and high resolution imagedata composed of 1280 pixels horizontally and 720 pixels vertically asillustrated in (c) of FIG. 3.

When a bandwidth through which image data is transmitted is narrow, onlythe low resolution image data serving as the base image is transmittedand the transmission terminal 10 on a receiving side can display only alow quality image in accordance with the transmitted low resolutionimage data.

When the bandwidth through which image data is transmitted is relativelywide, the low resolution image data serving as the base image and themedium resolution image data are transmitted and the transmissionterminal 10 on the receiving side can display a medium quality image inaccordance with the transmitted low resolution image data and mediumresolution image data.

When the bandwidth through which image data is transmitted is very wide,the low resolution image data serving as the base image, the mediumresolution image data, and the high resolution image data aretransmitted and the transmission terminal 10 on the receiving side candisplay a high quality image in accordance with the transmitted lowresolution image data, medium resolution image data, and high resolutionimage data.

In FIG. 1, the relaying apparatus 30 relays content data among thetransmission terminals 10. The transmission management apparatus 50performs login authentication of the transmission terminal 10 andmanages a transmission state of the transmission terminal 10, adestination list, and a transmission state of the relaying apparatus 30,for example, in an integrated fashion. Images represented by the imagedata may be moving images or still images, or both moving and stillimages.

A plurality of routers 70 a, 70 b, 70 c, 70 d, 70 ab, and 70 cd selectoptimal routes for image data and sound data. In the followingdescriptions, an arbitrary router among the routers 70 a, 70 b, 70 c, 70d, 70 ab, and 70 cd is expressed as a “router 70”.

The program supply apparatus 90 includes an HD (Hard Disk) 204 (refer toFIG. 6), which is described later. A transmission terminal controlprogram enabling the transmission terminal 10 to have various functionsis stored in the HD 204. The program supply apparatus 90 can transmitthe transmission terminal control program to the transmission terminal10.

In addition, the program supply apparatus 90 stores a relaying apparatusprogram enabling the relaying apparatus 30 to have various functions inthe HD 204 and can transmit the relaying apparatus program to therelaying apparatus 30.

Furthermore, the program supply apparatus 90 also stores a transmissionmanagement program enabling the transmission management apparatus 50 tohave various functions in the HD 204 and can transmit the transmissionmanagement program to the transmission management apparatus 50.

The transmission terminals 10 aa, 10 ab, 10 ac, . . . , and the router70 a are coupled to each other with a LAN 2 a so as to enabletransmission among them. Transmission terminals 10 ba, 10 bb, 10 bc, . .. , and the router 70 b are coupled to each other with a LAN 2 b so asto enable transmission among them.

The LANs 2 a and 2 b are coupled to each other with a dedicated line 2ab including the router 70 ab so as to enable transmission among them,and disposed in a predetermined region A. For example, the region A isJapan and the LAN 2 a is disposed in a business office in Tokyo whilethe LAN 2 b is disposed in a business office in Osaka.

Transmission terminals 10 ca, 10 cb, 10 cc, . . . , and the router 70 care coupled to each other with a LAN 2 c so as to enable transmissionamong them. Transmission terminals 10 da, 10 db, 10 dc, . . . , and therouter 70 d are coupled to each other with a LAN 2 d so as to enabletransmission among them.

The LANs 2 c and 2 d are coupled to each other with a dedicated line 2cd including the router 70 cd so as to enable transmission among them,and disposed in a predetermined region B. For example, the region B isthe United States of America and the LAN 2 c is disposed in a businessoffice in New York while the LAN 2 d is disposed in a business office inWashington, D.C. The regions A and B are coupled to each other with therouters 70 ab and 70 cd through the Internet 2 i so as to enable mutualtransmission.

The relaying apparatus 30, the transmission management apparatus 50, andthe program supply apparatus 90 are coupled to each transmissionterminal 10 through the Internet 2 i so as to enable the apparatuses toperform transmission to each transmission terminal 10. The relayingapparatus 30, the transmission management apparatus 50, and the programsupply apparatus 90 may be disposed in the region A or the region B, orin any region other than the regions A and B.

In the embodiment, a transmission network 2 of the embodiment includesthe LANs 2 a and 2 b, the dedicated lines 2 ab and 2 cd, the Internet 2i, and the LANs 2 c and 2 d. The transmission network 2 may include aunit in which transmission is performed wirelessly such as wirelessfidelity (Wi-Fi, registered trademark) or Bluetooth (registeredtrademark) besides the wired transmission.

In FIG. 1, four numbers indicated under each transmission terminal 10,the relaying apparatus 30, the transmission management apparatus 50,each router 70, and the program supply apparatus 90 simply representcommonly used IP addresses in IPv4. For example, the IP address of thetransmission terminal 10 aa is “1.2.1.3”. IPv6 may be also used insteadof IPv4. However, the explanation is made by using IPv4 for simpleexplanation.

Each transmission terminal 10 may be used in a video conference held inthe same room, or in a video conference held between an outdoor site andan indoor site or among the outdoor sites, in addition to a videoconference held among a plurality of business offices and a videoconference held among different rooms in the same business office. Wheneach transmission terminal 10 is used at an outdoor site, transmissionis performed wirelessly such as a cellular phone transmission network.

<<Hardware Structure of Embodiment>>

As illustrated in FIG. 4, the transmission terminal 10 includes ahousing 1021, an arm 1074, and a camera housing 1075. A front sidewall1021 a of the housing 1021 has a plurality of air intake holes 1021 e onalmost the entire surface thereof. A rear sidewall 1021 b of the housing1021 has a plurality of air exhaust holes (not illustrated) on almostthe entire area thereof. As a result, the transmission terminal 10 canintake external air at the front of the transmission terminal 10 throughthe air intake holes 1021 e and exhaust air toward the rear of thetransmission terminal 10 through the air exhaust holes by driving acooling fan included in the housing 1021. The front sidewall 1021 a hasa sound-collecting hole 1021 f at the central part thereof. Thesound-collecting hole 1021 f enables a built-in microphone 114 (refer toFIG. 5), which is described later, to collect sounds such as voices,other sounds, and noises.

The housing 1021 has an operation panel 1022 on the left side whenviewed from the front thereof. The operation panel 1022 is provided withoperation buttons 108, a power switch 109, and a plurality of soundoutput holes 1022 f through which sounds output from a built-in speaker115 (refer to FIG. 5), which is described later, pass. In addition, thehousing 1021 has a housing unit 1021 p formed in a recess so as to housethe arm 1074 and the camera housing 1075, on the right side when viewedfrom the front thereof.

The arm 1074 is mounted on the housing 1021 with a torque hinge 1073.For example, the arm 1074 is mounted so as to be rotatable in theup-down and left-right directions within a range of a pan angle θ1 of±180 degrees and within a range of a tilt angle θ2 of 90 degrees whenthe angle of the arm 1074 at the front is 0 degrees with respect to thehousing 1021. When the tilt angle θ2 is approximately 45 degrees, aclick feeling is generated.

The camera housing 1075 includes a built-in camera 112 (refer to FIG.5), which is described later. The camera 112 can be used to image a userand a room, for example. The camera housing 1075 has a torque hinge 1075a.

The camera housing 1075 is mounted on the arm 1074 with the torque hinge1075 a. For example, the camera housing 1075 is mounted on the arm 1074so as to be rotatable within a tilt angle θ3 of approximately 100degrees toward the front side of the transmission terminal 10 andapproximately 90 degrees toward the rear side of the transmissionterminal 10 when the angle of 0 degrees is defined as a state in whichthe camera housing 1075 and the arm 1074 are arranged in a straightline.

As illustrated in FIG. 5, the transmission terminal 10 includes acentral processing unit (CPU) 101 that controls overall operation of thetransmission terminal 10, a read only memory (ROM) 102 that storestherein a program used to drive the CPU 101 such as an initial programloader (IPL), a random access memory (RAM) 103 used as a working area ofthe CPU 101, a flash memory 104 that stores therein various types ofdata such as the transmission terminal control program, the image data,and the sound data, a solid state drive (SSD) 105 that controls readingof various types of data from or writing various types of data into theflash memory 104 under the control of the CPU 101, a media drive 107that controls reading of data from or writing (storing) of data into arecording medium 106 such as a flash memory, the operation button 108operated when a destination of the transmission terminal 10 is selected,for example, the power switch 109 that switches ON and OFF of a powersupply of the transmission terminal 10, and a network interface (I/F)111 that performs data transmission by utilizing the transmissionnetwork 2.

The transmission terminal 10 further includes the built-in camera 112that images a subject and acquires the image data under the control ofthe CPU 101, an image capturing device I/F 113 that controls driving ofthe camera 112, the microphone 114 that serves as a built-in soundcollector receiving sounds, the built-in speaker 115 that outputssounds, a sound input-output I/F 116 that processes input and output ofa sound signal between the microphone 114 and the speaker 115 under thecontrol of the CPU 101, a display I/F 117 that transmits image data tothe display 120 externally mounted under the control of the CPU 101, anexternal device connection I/F 118 that connects various externaldevices, and a bus line 110 that electrically connects theabove-described components, such as an address bus or a data bus.

The display 120 is a display device including liquid crystal or organicEL by which images of subjects and operation icons, for example, aredisplayed. The display 120 is coupled to the display I/F 117 with acable 120 c. The cable 120 c may be an analog RGB (VGA) signal cable, acomponent video cable, an HDMI high-definition multimedia interface(HDMI) signal cable, or a digital video interactive (DVI) signal cable.

The camera 112 includes a lens and a solid state image capturing devicethat converts light into charges so as to generate an electricallyavailable image of a subject. As the solid state image capturing device,a CMOS or a CCD is used, for example.

The external device connection I/F 118 can couple an external devicesuch as an external camera, an external microphone, or an externalspeaker with a universal serial bus (USB) cable, for example.

When an external camera is coupled to the external device connection I/F118, the CPU 101 drives the external camera prior to the built-in camera112. When an external microphone or an external speaker is coupled tothe external device connection I/F 118, the CPU 101 drives the externalmicrophone and the external speaker prior to the built-in microphone 114and the built-in speaker 115.

The recording medium 106 is attachable to and detachable from thetransmission terminal 10. An electrically erasable and programmable ROM(EEPROM) may be used for the transmission terminal 10, for example, as anon-volatile memory from which data is read or into which data iswritten under the control of the CPU 101, instead of the flash memory104.

The transmission terminal control program may be recorded into acomputer readable recording medium such as the recording medium 106 inan installable format or an executable format and distributed. Thetransmission terminal control program may be stored in the ROM 102instead of the flash memory 104.

As illustrated in FIG. 6, the transmission management apparatus 50includes a CPU 201 that controls the overall operation of thetransmission management apparatus 50, a ROM 202 that stores therein aprogram used to drive the CPU 201 such as an IPL, a RAM 203 that is usedas a working area of the CPU 201, the HD 204 that stores therein varioustypes of data such as the transmission management program, an HDD (HardDisk Drive) 205 that controls reading of various types of data from orwriting of various types of data into the HD 204 under the control ofthe CPU 201, a media drive 207 that controls reading data from orwriting (storing) data into a recording medium 206 such as a flashmemory, a display 208 that displays various types of information such asa cursor, menus, windows, characters, or images, a network I/F 209 thatperforms data transfer by utilizing the transmission network 2, akeyboard 211 provided with a plurality of keys for inputting characters,numerical values, and various instructions, a mouse 212 that is used toselect and execute various instructions, select items to be processed,and move the cursor, a compact disc read only memory (CD-ROM) drive 214that controls reading of various types of data from or writing ofvarious types of data into a CD-ROM 213 as an example of anattachable-detachable recording medium, and a bus line 210 thatelectrically connects the above-described components, such as an addressbus or a data bus.

The transmission management program may be recorded into a computerreadable recording medium such as the recording medium 206 and theCD-ROM 213 in an installable format or an executable format anddistributed. The transmission management program may be stored in theROM 202 instead of the HD 204.

The relaying apparatus 30 has the same hardware structure as that of thetransmission management apparatus 50. The description thereof is, thus,omitted. The HD 204 stores therein the relaying apparatus program thatcontrols the relaying apparatus 30.

Also in this case, the relaying apparatus program may be recorded into acomputer readable recording medium such as the recording medium 206 andthe CD-ROM 213 in an installable format or an executable format anddistributed. The relaying apparatus program may be stored in the ROM 202instead of the HD 204.

The program supply apparatus 90 has the same hardware structure as thatof the transmission management apparatus 50. The description thereof is,thus, omitted. The HD 204 stores therein a program supply apparatusprogram that controls the program supply apparatus 90.

Also in this case, the program supply apparatus program may be recordedinto a computer readable recording medium such as the recording medium206 and the CD-ROM 213 in an installable format or an executable formatand distributed. The program supply apparatus program may be stored inthe ROM 202 instead of the HD 204.

As the above-described computer readable recording medium, a compactdisc recordable (CD-R), a digital versatile disk (DVD), or a Blue-raydisc is applicable, for example.

<<Functional Structure of Embodiment>>

As illustrated in FIG. 7, the transmission terminal 10, the relayingapparatus 30, and the transmission management apparatus 50 are coupledsuch that they can transmit data through the transmission network 2. Theprogram supply apparatus 90 illustrated in FIG. 1 is omitted in FIG. 7because the program supply apparatus 90 does not directly relate to datatransmission in a video conference.

<Functional Structure of Transmission Terminal>

The transmission terminal 10 includes a transmitting-receiving unit 11,an operation input reception unit 12, a login request unit 13, an imagecapturing unit 14, a sound input unit 15 a, a sound output unit 15 b, adisplay control unit 17, and a storage-read processing unit 19. Theabove-described components are achieved by the CPU 101 that executes thetransmission terminal control program loaded on the RAM 103 from theflash memory 104. The transmission terminal 10 includes a storage unit1000 that is structured by the RAM 103 and the flash memory 104.

Functional Structures of Transmission Terminal

The transmitting-receiving unit 11, which is achieved by the CPU 101 andthe network I/F 111, transmits and receives various types of data andinformation between itself and other transmission terminals 10 or theapparatuses 30, 50, and 90 through the transmission network 2. Thetransmitting-receiving unit 11 functions as the transmitting unit andthe receiving unit of the transmission terminal 10.

The transmitting-receiving unit 11 starts receiving state informationindicating the states of the transmission terminals 10 that arecandidates of a connecting destination in a video conference from thetransmission management apparatus 50 before starting the videoconference with a desired destination terminal.

The state information indicates not only an operation state of whethereach transmission terminal 10 is online or offline but also a detailedoperation state such as whether each transmission terminal 10 is onlineand transmission is enabled or whether each transmission terminal 10 isonline and in a transmission operation.

In addition, the state information indicates not only the operationstate of each transmission terminal 10 but also various states in thetransmission terminal 10. For example, a state in which the cable 120 cis come off from the transmission terminal 10, a state in which thetransmission terminal 10 outputs sounds but no images, and a state inwhich the transmission terminal 10 outputs no sounds (MUTE). For easyunderstanding, a case is described in which the state informationindicates the operation state of each transmission terminal 10, in thefollowing descriptions.

The operation input reception unit 12, which is achieved by the CPU 101,the operation button 108, and the power switch 109, receives varioustypes of inputs from a user. For example, once a user turns on the powerswitch 109, the operation input reception unit 12 receives the power ONoperation and causes the power supply of the transmission terminal 10 tobe turned on.

The login request unit 13, which is achieved by the CPU 101, once thepower ON operation is received, transmits login request informationindicating a request for login and the current IP address of thetransmission terminal 10 to the transmission management apparatus 50from the transmitting-receiving unit 11 through the transmission network2.

When the user switches the power switch 109 from the ON state to the OFFstate, the operation input reception unit 12 completely turns off thepower supply of the transmission terminal 10 after thetransmitting-receiving unit 11 transmits the state informationindicating that the power supply is to be turned off to the transmissionmanagement apparatus 50. As a result, the transmission managementapparatus 50 can grasp the fact that the power supply of thetransmission terminal 10 has been turned off from the ON state.

The image capturing unit 14, which is achieved by the CPU 101, thecamera 112, and the image capturing device I/F 113, images a subject andoutputs the resulting image data to the transmitting-receiving unit 11.The camera 112 functions as an imaging apparatus and the image capturingdevice I/F 113 functions as an image data input unit.

The sound input unit 15 a, which is achieved by the CPU 101 and thesound input-output I/F 116, functions as a sound data input unit. Thesound input unit 15 a, to which a sound signal representing a soundcollected by the microphone 114 is input, converts the received soundsignal into sound data.

The sound output unit 15 b, which is achieved by the CPU 101 and thesound input-output I/F 116, converts sound data into a sound signal andoutputs the converted sound signal to the speaker 115 so as to cause thespeaker 115 to output a sound.

The display control unit 17, which is achieved by the CPU 101 and thedisplay I/F 117, combines pieces of image data that have differentresolutions and are received by the transmitting-receiving unit 11, andtransmits the combined image data to the display 120 so as to cause thedisplay 120 to display an image represented by the image data thereon.

The display control unit 17 transmits information relating to adestination list received by the transmitting-receiving unit 11 from thetransmission management apparatus 50 to the display 120 so as to causethe display 120 to display the destination list thereon.

The storage-read processing unit 19, which is achieved by the CPU 101and the SSD 105, stores various types of data in the storage unit 1000and reads various types of data stored in the storage unit 1000.

The storage unit 1000 stores therein an identifier (hereinafter referredto as a “terminal ID”) and a password for identifying the transmissionterminal 10, for example. In addition, the storage unit 1000 is alsoused as a receiving buffer for image data and sound data that arereceived when a video conference is held with a destination terminal.

The terminal ID in the embodiment indicates information used to uniquelyidentify the transmission terminal 10, such as languages, characters,symbols, or various signs. The terminal ID may be information obtainedby combining at least two of the languages, characters, symbols, andvarious sings.

<Functional Structure of Transmission Management Apparatus>

The transmission management apparatus 50 includes atransmitting-receiving unit 51, a terminal authentication unit 52, astate management unit 53, a terminal extraction unit 54, a terminalstate acquisition unit 55, and a storage-read processing unit 59. Theabove-described components are achieved by the CPU 201 that executes thetransmission management program loaded on the RAM 203 from the HD 204.The transmission management apparatus 50 includes a storage unit 5000composed of the HD 204.

Terminal Authentication Management Table

In the storage unit 5000, a terminal authentication management DB 5002having a terminal authentication management table illustrated in FIG. 8is structured. In the terminal authentication management table,passwords are managed in association with the respective terminal IDs ofall of the transmission terminals 10 managed by the transmissionmanagement apparatus 50. For example, the terminal authenticationmanagement table illustrated in FIG. 8 indicates that the terminal ID ofthe transmission terminal 10 aa is “01 aa” and the password of thetransmission terminal 10 aa is “aaaa”.

Terminal Management Table

In the storage unit 5000, a terminal management DB 5003 having aterminal management table illustrated in FIG. 9 is structured. Theterminal management DB 5003 functions as a terminal management tablestorage unit.

In the terminal management table, an identification name of thetransmission terminal 10 (hereinafter referred to as a “terminal name”),an operation state of the transmission terminal 10, a receiving date atwhich the login request information to login the transmission system 1is received by the transmission management apparatus 50, and the IPaddress of the transmission terminal 10 are managed in association witheach other for each terminal ID of the transmission terminals 10.

For example, the terminal management table illustrated in FIG. 9indicates that the terminal name is “AA terminal, Tokyo business office,Japan”, the operation state is “online (transmission is enabled)”, thedata at which the login request information was received by thetransmission management apparatus 50 is “13:40 on Nov. 10, 2009”, andthe IP address is “1.2.1.3” for the transmission terminal 10 aa havingthe terminal ID of “01 aa”.

The terminal ID of the terminal management table is uniquely allocatedwhen the transmission terminal 10 is registered in the transmissionsystem 1. The terminal name is registered or changed by an administratorof the transmission management apparatus 50. The terminal name may beregistered or changed in response to a request made from thetransmission terminal 10 to the transmission management apparatus 50.

The operation state of “online (transmission is enabled)” indicates thatthe transmission terminal 10 has logged in the transmission system 1 butis not attending a video conference. The operation state of “online (intransmission)” indicates that the transmission terminal 10 has logged inthe transmission system 1 and is attending a video conference. Theoperation state of “offline” indicates that the transmission terminal 10has not logged in the transmission system 1.

Destination List Management Table

Furthermore, in the storage unit 5000, a destination list management DB5004 having a destination list management table illustrated in FIG. 10is structured. The destination list management DB 5004 functions as adestination list management table storage unit.

In the destination list management table, all of the terminal IDs of thedestination terminals registered as the candidates of the destinationterminal are managed in association with the terminal ID of the requestsource terminal that requests a start of a video conference.

For example, the destination list management table illustrated in FIG.10 indicates that the candidates of the destination terminal to whichthe transmission terminal 10 aa having the terminal ID of “01 aa”requests a start of a video conference are the transmission terminal 10ab having the terminal ID of “01 ab”, the transmission terminal 10 bahaving the terminal ID of “01 ba”, and the transmission terminal 10 dbhaving the terminal ID of “01 db”. The candidate of the destinationterminal is added or deleted in response to a request made from thetransmission terminal 10 to the transmission management apparatus 50.

Functional Structures of Transmission Management Apparatus

The transmitting-receiving unit 51, which is achieved by the CPU 201 andthe network I/F 209, transmits and receives various types of data andinformation between itself and other transmission terminals 10 or theapparatuses 30 and 90 through the transmission network 2.

The terminal authentication unit 52, which is achieved by the CPU 201,searches the terminal authentication management DB 5002 of the storageunit 5000 by using the terminal ID and the password that are included inthe login request information received through thetransmitting-receiving unit 51 as searching keys, and performs terminalauthentication by determining whether the same terminal ID and passwordare managed in the terminal authentication management DB 5002.

The state management unit 53, which is achieved by the CPU 201, storesthe operation state, the receiving date at which the transmissionmanagement apparatus 50 has received the login request information, andthe IP address in the terminal management DB 5003 (refer to FIG. 9) andmanages them in association with the terminal ID of the request sourceterminal so as to manage the operation state of the request sourceterminal that makes the login request.

The state management unit 53 changes the operation state of thetransmission terminal 10 in the terminal management DB 5003 (refer toFIG. 9) from online to offline in accordance with the state informationthat is sent from the transmission terminal 10 and indicates that thepower supply is to be turned off when a user turns off the power switch109 of the transmission terminal 10 from the ON state.

The terminal extraction unit 54, which is achieved by the CPU 201,searches the destination list management DB 5004 (refer to FIG. 10) byusing the terminal ID of the request source terminal that has made thelogin request as a searching key, and extracts the terminal IDs of thecandidates of the destination terminal of the request source terminal.

In addition, the terminal extraction unit 54 searches the destinationlist management DB 5004 (refer to FIG. 10) by using the terminal ID ofthe request source terminal that has made the login request as asearching key, and extracts the terminal IDs of the other request sourceterminals that register the terminal ID of the request source terminalas the candidate of the destination terminal thereof.

The terminal state acquisition unit 55, which is achieved by the CPU201, searches the terminal management DB 5003 (refer to FIG. 9) by usingthe terminal IDs of the candidates of the destination terminal extractedby the terminal extraction unit 54 as searching keys and reads theoperation state for each detected terminal ID.

As a result, the terminal state acquisition unit 55 can acquire theoperation states of the candidates of the destination terminal of therequest source terminal that has made the login request. Furthermore,the terminal state acquisition unit 55 searches the terminal managementDB 5003 by using the terminal IDs extracted by the terminal extractionunit 54 as searching keys and acquires the operation state of therequest source terminal that has made the login request.

The storage-read processing unit 59, which is achieved by the CPU 201and the HDD 205, stores various types of data in the storage unit 5000and reads various types of data stored in the storage unit 5000.

<<Processing or Operation of Embodiment>>

Operation of the transmission system 1 according to the embodiment isdescribed below. FIG. 11 is a sequence diagram illustrating preparatorystage operation until the transmission terminal 10 reaches a preparatorystate to attend a video conference. FIG. 11 illustrates an example inwhich the transmission terminal 10 aa reaches the preparatory state. Inthe preparatory stage operation, various types of information aretransmitted and received in the management information session SEI(refer to FIG. 2).

When a user of the transmission terminal 10 aa turns on the power switch109 of the transmission terminal 10 aa, the operation input receptionunit 12 receives the power ON operation and causes the power supply tobe turned on (step S21). The login request unit 13, once the power ONoperation is received, transmits the login request informationindicating a request for login to the transmission management apparatus50 from the transmitting-receiving unit 11 of the transmission terminal10 aa through the transmission network 2 (step S22).

The login request information includes the terminal ID and the passwordto identify the transmission terminal 10 aa serving as a login requestsource. The terminal ID and the password are read from the storage unit1000 by the storage-read processing unit 19.

Upon receiving the login request information transmitted from thetransmission terminal 10 aa, the transmission management apparatus 50can grasp the IP address of the transmission terminal 10 aa serving as atransmission side.

Then, the terminal authentication unit 52 of the transmission managementapparatus 50 searches the terminal authentication management DB 5002 ofthe storage unit 5000 (refer to FIG. 8) by using the terminal ID and thepassword that are included in the login request information receivedthrough the transmitting-receiving unit 51 as searching keys, andperforms terminal authentication by determining whether the sameterminal ID and password as the searching keys are managed in theterminal authentication management DB 5002 (step S23).

If the terminal authentication unit 52 determines that the same terminalID and password as the searching keys are not managed, i.e., if it isdetermined that the login request is not transmitted from thetransmission terminal 10 having use authority, thetransmitting-receiving unit 51 transmits authentication resultinformation indicating the authentication result obtained by theterminal authentication unit 52 to the transmission terminal 10 aa thathas made the login request through the transmission network 2.Thereafter, the operation of the preparatory stage ends.

On the other hand, if the terminal authentication unit 52 determinesthat the same terminal ID and password as the searching keys aremanaged, i.e., it is determined that the login request is transmittedfrom the transmission terminal 10 having use authority, the statemanagement unit 53 stores the terminal ID, the operation state, thereceiving date of the login request information, and the IP address ofthe transmission terminal 10 aa in the terminal management DB 5003(refer to FIG. 9) in association with one another (step S24).

As a result, as illustrated in FIG. 9, the terminal management tablemanages the terminal ID “01 aa”, the operation state “online(transmission is enabled)”, the receiving date “13:40 on Nov. 10, 2009”,and the IP address “1.2.1.3” of the transmission terminal 10 aa inassociation with one another.

Then, the transmitting-receiving unit 51 of the transmission managementapparatus 50 transmits the authentication result information indicatingthe authentication result obtained by the terminal authentication unit52 to the transmission terminal 10 aa that has made the login requestthrough the transmission network 2 (step S25).

Then, the terminal extraction unit 54 of the transmission managementapparatus 50 searches the destination list management DB 5004 (refer toFIG. 10) by using the terminal ID “01 aa” of the transmission terminal10 aa that has made the login request as a searching key, and extractsthe terminal IDs of the candidates of the destination terminal of thetransmission terminal 10 aa (step S26).

In this case, the terminal IDs “01 ab”, “01 ba”, and “01 db” of thetransmission terminals 10 ab, 10 ba, and 10 db that are the destinationterminals of the terminal ID “01 aa” of the transmission terminal 10 aaare extracted.

Then, the terminal state acquisition unit 55 of the transmissionmanagement apparatus 50 searches the terminal management DB 5003 (referto FIG. 9) by using the terminal IDs “01 ab”, “01 ba”, and “01 db” ofthe candidates of the destination terminal extracted by the terminalextraction unit 54 as searching keys and reads the operation states ofthe terminal IDs extracted by the terminal extraction unit 54 as“offline”, “online (transmission is enabled)”, and “online (intransmission)”. As a result, the terminal state acquisition unit 55acquires the respective operation states of the transmission terminals10 ab, 10 ba, and 10 db(step S27).

Then, the transmitting-receiving unit 51 of the transmission managementapparatus 50 transmits, to the transmission terminal 10 aa through thetransmission network 2, the terminal IDs “01 ab”, “01 ba”, and “01 db”used as the searching keys at step S27, and the destination stateinformation including the operation states of the respectivetransmission terminals 10 ab, 10 ba, and 10 db corresponding to therespective terminal IDs, which are “offline”, “online (transmission isenabled)”, and “online (in transmission)” (step S28).

As a result, the transmission terminal 10 aa can grasp the currentoperation states, each of which is “offline”, “online (transmission isenabled)”, and “online (in transmission)”, of the transmission terminals10 ab, 10 ba, and 10 db that are the candidates of the destinationterminal.

Furthermore, the terminal extraction unit 54 of the transmissionmanagement apparatus 50 searches the destination list management DB 5004(refer to FIG. 10) by using the terminal ID “01 aa” of the transmissionterminal 10 aa that has made the login request as a searching key, andextracts the terminal IDs of the other transmission terminals thatregister the terminal ID “01 aa” of the transmission terminal 10 aa asthe candidate of the destination terminal (step S29). For example, inthe destination list management table illustrated in FIG. 10, theterminal IDs “01 ab”, “01 ba”, and “01 db” are extracted.

Then, the state management unit 53 of the transmission managementapparatus 50 searches the terminal management DB 5003 (refer to FIG. 9)by using the terminal ID “01 aa” of the transmission terminal 10 aa thathas made the login request as a searching key and acquires the operationstate, which is “online (transmission is enabled)”, of the transmissionterminal 10 aa that has made the login request (step S30).

Then, the transmitting-receiving unit 51 of the transmission managementapparatus 50 transmits destination state information including theterminal ID “01 aa” of the transmission terminal 10 aa and the operationstate “online (transmission is enabled)” that are acquired at step S30to the transmission terminals 10 ba and 10 db each operation state ofwhich is “online” in the terminal management DB 5003 (refer to FIG. 9)among the transmission terminals 10 ab, 10 ba, and 10 db that areidentified with the terminal IDs “01 ab”, “01 ba”, and “01 db” extractedat step S29 (step S31-1 and step S31-2).

When transmitting the destination state information to the transmissionterminals 10 ba and 10 db, the transmitting-receiving unit 51 refers tothe IP addresses of the transmission terminals managed in the terminalmanagement table illustrated in FIG. 9 using the terminal IDs “01 ba”and “01 db”.

As a result, the terminal ID “01 aa” and the operation state “online(transmission is enabled)” of the transmission terminal 10 aa that hasmade the login request can be transmitted to the transmission terminals10 db and 10 ba that can perform transmission to the transmissionterminal 10 aa that has made the login request as the destination.

When step S28 of the preparatory stage operation is complete, thedisplay control unit 17 of the transmission terminal 10 aa highlights,on the display 120, the information of the terminals attending the videoconference, i.e., the transmission terminal 10 db operation state ofwhich is “online (in transmission)” or “online (transmission isenabled)”, from the information of the destination list displayed on thedisplay 120, for example. As a result, the display control unit 17allows a user to recognize the transmission terminal 10 attending orcapable of attending the video conference.

FIG. 12 is a sequence diagram illustrating conference attendanceoperation until the transmission terminal 10 reaches an attendance statein which the transmission terminal 10 is attending a video conference.FIG. 12 illustrates an example in which the transmission terminal 10 aareaches the attendance state. In the conference attendance operation,various types of information are transmitted and received in themanagement information session SEI (refer to FIG. 2).

Once a user presses the operation button 108 to select an attendance ata video conference, the operation input reception unit 12 receives arequest for an attendance at the video conference held with thetransmission terminal 10 db (step S41).

In response to the request, the transmitting-receiving unit 11 of thetransmission terminal 10 aa transmits attendance request informationindicating the attendance at the video conference and including theterminal ID “01 aa” of the transmission terminal 10 aa and the terminalID “01 db” of the transmission terminal 10 db to the transmissionmanagement apparatus 50 (step S42).

As a result, the transmitting-receiving unit 51 of the transmissionmanagement apparatus 50 receives the attendance request information andcan confirm the IP address “1.2.1.3” of the transmission terminal 10 aaserving as a transmission source.

Then, the state management unit 53 of the transmission managementapparatus 50 searches by using the terminal ID “01 aa” of thetransmission terminal 10 aa included in the attendance requestinformation as a searching key and sets “online (in transmission)” asthe operation state of the transmission terminal 10 aa that has made theattendance request (step S43).

Then, the transmitting-receiving unit 51 of the transmission managementapparatus 50 transmits start request information including the terminalID “01 aa” of the transmission terminal 10 aa to the transmissionterminal 10 db though the transmission network 2 (step S44). As aresult, the transmission terminal 10 db can grasp which transmissionterminal 10 has requested the attendance at the video conference.

In the terminal management DB 5003 illustrated in FIG. 9, the operationstate of the transmission terminal 10 cb is “online (in transmission)”.Accordingly, the transmitting-receiving unit 51 of the transmissionmanagement apparatus 50 transmits the start request informationincluding the terminal ID “01 aa” of the transmission terminal 10 aa tothe transmission terminal 10 cb through the transmission network 2.Detailed description thereof is, however, omitted herein for easyunderstanding of the invention.

Then, the transmission terminal 10 db transmits receiving completioninformation indicating the completion of the receiving of the startrequest information to the transmission management apparatus 50 from thetransmitting-receiving unit 11 through the transmission network 2 (stepS45).

Then, the transmitting-receiving unit 51 of the transmission managementapparatus 50 transmits relay start request information indicating arequest for starting a relay to the relaying apparatus 30 through thetransmission network 2 (step S46). The relay start request informationincludes the IP address “1.2.1.3” of the transmission terminal 10 aa andthe IP address “1.3.2.4” of the transmission terminal 10 db.

As a result, the relaying apparatus 30 establishes a session fortransmitting three pieces of image data of low resolution, mediumresolution, and high resolution and sound data between the transmissionterminals 10 aa and 10 db(step S47). In this way, the transmissionterminal 10 aa can attend the video conference held with thetransmission terminal 10 db.

Meanwhile, the transmitting-receiving unit 51 of the transmissionmanagement apparatus 50 casts terminal state change informationincluding the terminal ID “01 aa” and the operation state “online (intransmission)” of the transmission terminal 10 aa into each transmissionterminal 10 registered in the terminal management DB 5003 (refer to FIG.9) (step S48). As a result, each transmission terminal 10 havingreceived the terminal state change information can store and display theoperation state of the transmission terminal 10 aa having the terminalID “01 aa” if needed.

FIG. 13 is a sequence diagram illustrating data transmission operationbetween the transmission terminals 10. In the data transmissionoperation illustrated in FIG. 13, image data and sound data aretransmitted and received in the image/sound data session SED (refer toFIG. 2).

Once the session is established between the transmission terminals 10 aaand 10 db as described with reference to FIG. 12, the transmissionterminal 10 aa transmits, to the relaying apparatus 30 through thetransmitting-receiving unit 51, the image data taken by the imagecapturing unit 14 and sound data into which the sound input unit 15 aconverts a received sound signal (step S60).

Upon receiving the image data and the sound data from the transmissionterminal 10 aa, the relaying apparatus 30 transmits the received imagedata and sound data to each of the transmission terminals 10 aa and 10db that are attending the video conference (step S61-1 and step S61-2).

Upon receiving the image data and the sound data from the relayingapparatus 30, each of the transmission terminals 10 aa and 10 db allowsthe display control unit 17 to cause the display 120 to display theimage represented by the received image data and allows the sound outputunit 15 b to cause the speaker 115 to output the sound represented bythe received sound data (step S62-1 and step S62-2).

Then, the transmission terminal 10 db transmits, to the relayingapparatus 30 through the transmitting-receiving unit 51, image datataken by the image capturing unit 14 and sound data into which the soundinput unit 15 a converts a received sound signal (step S63).

Upon receiving the image data and the sound data from the transmissionterminal 10 db, the relaying apparatus 30 transmits the received imagedata and sound data to each of the transmission terminals 10 aa and 10db that are attending the video conference (step S64-1 and step S64-2).

Upon receiving the image data and the sound data from the relayingapparatus 30, each of the transmission terminals 10 aa and 10 db allowsthe display control unit 17 to cause the display 120 to display theimage represented by the received image data and allows the sound outputunit 15 b to cause the speaker 115 to output the sound represented bythe received sound data (step S65-1 and step S65-2).

In this way, the transmission terminals 10 aa and 10 db can have a videoconference therebetween through the relaying apparatus 30. FIG. 13illustrates two transmission terminals 10, i.e., the transmissionterminals 10 aa and 10 db, attending the video conference for easyunderstanding. Even if the number of transmission terminals 10 attendingthe video conference is equal to or more than three, image data andsound data are transmitted in the same manner as the data transmissionoperation illustrated in FIG. 13.

An image display of the transmission terminal 10 is described below. Inthe embodiment, the display control unit 17 has two display modes of anall-image display mode and an information display mode. Switching of thedisplay modes is performed in accordance with operation of the operationbutton 108, for example.

In the all-image display mode as illustrated in FIG. 14, the displaycontrol unit 17 of the transmission terminal 10 causes the display 120to display all of the images transmitted from each transmission terminal10 attending a video conference.

In the display screen illustrated in FIG. 14, a first image area 500having a relatively large area and a plurality of second image areas 510each having a relatively small area are allocated. For example, imagesrepresented by pieces of image data transmitted from the transmissionterminals 10 attending the video conference are displayed in the secondimage areas 510 while an image represented by image data of a maintransmission terminal among the transmission terminals 10 attending thevideo conference is displayed in the first image area 500.

For example, the display control unit 17 specifies a transmissionterminal that is the transmission source of sound data representing thevoice in the received sound data as a major terminal among thetransmission terminals 10 attending the video conference. A voice streamis detected for each piece of the received sound data. The sound datarepresenting the voice is sound data determined that it has the voicestream. The detection of the voice stream can be achieved by using knowntechniques (e.g., refer to NIIMI, Yasuhisa. Speech Recognition. Japan.Kyoritsu Publishing, Co. 1979. pages 68 to 72).

On the other hand, in the information display mode as illustrated inFIG. 15, the display control unit 17 of the transmission terminal 10causes the display 120 to display terminal information including atleast the terminal names and terminal IDs of the transmission terminals10 attending the video conference.

To the display screen illustrated in FIG. 15, an image display area 520for displaying an image and a terminal information display area 530 fordisplaying the terminal information are allocated. For example, in theterminal information display area 530, pieces of the terminalinformation of the transmission terminals 10 attending the videoconference are displayed as a list.

The terminal information having no terminal name displayed among thepieces of terminal information displayed in the list represents thetransmission terminal 10 that is not registered as the candidate of thedestination terminal of the terminal serving as a transmission terminalin the destination list management DB 5004 (refer to FIG. 10).

For example, in the display screen illustrated in FIG. 15, the terminalname of the transmission terminal 10 db is displayed because thetransmission terminal 10 db is registered in the destination listmanagement DB 5004 as the candidate of the destination terminal of thetransmission terminal 10 aa while the terminal name of the transmissionterminal 10 cb is not displayed because the transmission terminal 10 cbis not registered in the destination list management DB 5004 as thecandidate of the destination terminal of the transmission terminal 10aa.

In the image display area 520, an image represented by image data of amajor transmission terminal is displayed among the transmissionterminals 10 attending the video conference. For example, the displaycontrol unit 17 specifies a transmission terminal that is thetransmission source of sound data representing the voice in the receivedsound data, as a major transmission terminal among the transmissionterminals 10 attending the video conference. The display control unit 17may specify a selected transmission terminal as a major transmissionterminal when the operation input reception unit 12 receives informationindicating that a certain transmission terminal is selected among thetransmission terminals 10 attending the video conference in accordancewith a user's operation of the operation button 108.

FIG. 16 is a sequence diagram illustrating terminal information displayoperation in which terminal information to be displayed in the terminalinformation display area 530 is displayed in the terminal informationdisplay area 530 when the display mode is switched to the informationdisplay mode in the transmission terminal 10. In the terminalinformation display operation illustrated in FIG. 16, various types ofinformation are transmitted and received in the management informationsession SEI.

First, the transmission terminal 10 transmits a terminal informationrequest signal indicating a request of the terminal information of thetransmission terminal attending a video conference to the transmissionmanagement apparatus 50 (step S70). Upon receiving the terminalinformation request signal, the terminal state acquisition unit 55 ofthe transmission management apparatus 50 searches the terminalmanagement DB 5003 (refer to FIG. 9) of the storage unit 5000 by usingthe IP address of the transmission source of the terminal informationrequest signal as a searching key and acquires the terminal ID of thetransmission terminal that transmits the terminal information requestsignal (step S71).

Then, the terminal state acquisition unit 55 searches the terminalmanagement DB 5003 for the terminal ID and the terminal name with theoperation condition “online (in transmission)” (step S72). In theembodiment, the terminal state acquisition unit 55 detects the terminalIDs “01 aa”, “01 cb”, and “01 db”. The operation state of thetransmission terminal having the terminal ID “01 aa” is set as “online(in transmission)” at step S43.

Then, the terminal state acquisition unit 55 searches the destinationlist management DB 5004 (refer to FIG. 10) of the storage unit 5000 byusing the terminal ID detected at step S71 (“01 aa” in the embodiment)as a searching key and acquires the terminal IDs of the candidates ofthe destination terminal of the transmission source of the terminalinformation request signal (step S73).

For example, when the terminal ID of the transmission terminal thattransmits the terminal information request signal is “01 aa”, theterminal IDs “01 ab”, “01 ba”, and “01 db” are acquired by the terminalstate acquisition unit 55.

Then, the terminal state acquisition unit 55 determines whether each ofthe terminal IDs acquired at step S72 is included in the terminal ID ofthe transmission source of the terminal information request signal orthe terminal IDs acquired at step S73. If it is determined that theterminal ID is included, the terminal state acquisition unit 55 causesthe transmitting-receiving unit 51 to reply the included terminal ID andthe terminal name to the transmission source of the terminal informationrequest signal. If it is determined that the terminal ID is notincluded, the terminal state acquisition unit 55 causes thetransmitting-receiving unit 51 to reply only the terminal ID to thetransmission source of the terminal information request signal (stepS74).

For example, when the terminal ID of the transmission terminal thattransmits the terminal information request signal is “01 aa”, theterminal IDs “01 aa” and “01 db” and the terminal names “AA terminal,Tokyo business office, Japan” and “DB terminal, Washington, D.C.business office, USA” of the transmission terminals 10 aa and 10 db, andthe terminal ID “01 cb” of the transmission terminal 10 cb aretransmitted to the transmission terminal 10 aa that is the transmissionsource of the terminal information request signal.

The display control unit 17 of the transmission terminal 10 havingreceived the reply displays the reply contents in the terminalinformation display area 530 as the display screen illustrated in FIG.15 (step S75).

<<Major Effect of Embodiment>>

As described above, the transmission system 1 according to theembodiment causes the transmission management apparatus 50 to reply theinformation of the transmission terminals 10 attending a videoconference. As a result, a user of each of the transmission terminals 10can grasp which transmission terminal 10 is attending the videoconference regardless of the number of transmission terminals 10attending the video conference.

Accordingly, the transmission system 1 enables a user to know the otherparty at a video conference without requiring the user to ask the otherparty in conversation. As a result, time taken for the video conferencecan be reduced. In the transmission system 1, the terminal name of thetransmission terminal that is not registered as the destination is notdisplayed, enabling the attendance of an unknown party at the videoconference to be informed. As a result, the video conference can proceedwith careful attention to discussion contents.

In the transmission system 1, image data of a major transmissionterminal remains displayed even when terminal information is displayedon the display 120. As a result, a user can grasp a situation of a sitethat currently leads the video conference.

Supplemental Explanation of Embodiment

The relaying apparatus 30, the transmission management apparatus 50, andthe program supply apparatus 90 in the embodiment may be structured by asingle computer. The units (function or means) of them may be dividedand the divided units may be structured by a plurality of computers eachallocated for any unit.

When the program supply apparatus 90 is structured by a single computer,a program transmitted by the program supply apparatus 90 may betransmitted as a plurality of divided modules or transmitted withoutbeing divided.

When the program supply apparatus 90 is structured by a plurality ofcomputers, a program may be transmitted from the computers as aplurality of divided modules.

The recording medium, such as CD-ROM, in which the transmission terminalcontrol program, the relaying apparatus program, and the transmissionmanagement program of the embodiment are stored, the HD 204 that storestherein the programs, and the program supply apparatus 90 including theHD 204 are used as program products when the transmission terminalcontrol program, the relaying apparatus program, and the transmissionmanagement program are provided to a user and the like domestically oroverseas.

As an example of quality of an image represented by image data relayedby the relaying apparatus 30, attention is paid on the resolution of theimage represented by the image data and the resolution is managed. Theimage quality is not limited to the resolution. As other examples ofquality, attention may be paid on depth of image quality of the imagerepresented by the image data, a sampling frequency of sound in sounddata, and a bit length of sound in sound data and the quality may bemanaged. Sound data may be transmitted and received by being dividedinto three pieces of data having different resolutions (high resolution,medium resolution, and low resolution).

In FIG. 9, the IP address of the transmission terminal 10 is managed.However, the item to be managed is not limited to the IP address. Anyinformation can be used as long as it can be used to identify thetransmission terminal 10 on the transmission network 2. For example, afully qualified domain name (FQDN) of the transmission terminal 10 maybe managed. In this case, the IP address corresponding to the FQDN isacquired by a known domain name system (DNS) server.

In the embodiment, the video conference system is described as anexample of the transmission system 1. However, the transmission system 1is not limited to be applied to the video conference system. Thetransmission system 1 may be applicable to a telephone system such as anInternet Protocol (IP) telephone and an Internet telephone.

The transmission system 1 may be a car navigation system. In this case,the transmission terminal 10 on one side corresponds to a car navigationsystem mounted on a vehicle while the transmission terminal 10 on theother side corresponds to a management terminal or a management serverof a management center that manages the car navigation, or another carnavigation system mounted on another vehicle. In the transmission system1, the transmission terminals 10 may be structured with cell phones.

In the embodiment, image data and sound data are described as examplesof the content data. However, content data is not limited to the imagedata and the sound data. Touch data may be applicable. In this case, asense of touch obtained by a user at a transmission terminal on one sideis transmitted to another transmission terminal on the other side.

The content data may be olfactory (smell) data. In this case, an aroma(smell) at a transmission terminal on one side is transmitted to anothertransmission terminal on the other side. The content data may be atleast one piece of image data, sound data, touch data, and olfactorydata.

In the embodiment, the video conference is held by using thetransmission system 1. However, the transmission system 1 is not limitedto be used for the video conference. The transmission system 1 may beused for general conversations among family members or friends orinformation supply in one direction.

As described above, the embodiment enables users who use the respectivetransmission terminals to grasp which transmission terminal is attendinga conference regardless of the number of transmission terminalsattending the conference.

Although the invention has been described with respect to specificembodiments for a complete and clear disclosure, the appended claims arenot to be thus limited but are to be construed as embodying allmodifications and alternative constructions that may occur to oneskilled in the art that fairly fall within the basic teaching herein setforth.

The invention claimed is:
 1. A first transmission terminal, comprising:a transmitter configured to transmit, through a network, a terminalinformation request to a transmission management apparatus that storestransmission states of a plurality of transmission terminals and piecesof information identifying the respective transmission terminals so thatthe transmission states and the pieces of information are associatedwith each other, the terminal information request indicating a requestfor information identifying at least a second transmission terminal ofthe transmission terminals, the second transmission terminal being incommunication with the first transmission terminal via a sessionestablished with the first transmission terminal; a receiver configuredto receive, from the transmission management apparatus, a piece ofinformation identifying the second transmission terminal that isacquired based on the transmission state by the transmission managementapparatus in response to the terminal information request; and a displaycontrol circuit configured to cause a display to display a listincluding the piece of information identifying the second transmissionterminal received by the receiver, in response to an input operation tothe first transmission terminal.
 2. The first transmission terminalaccording to claim 1, further comprising an operation input receiverconfigured to receive input from a user, wherein the display controlcircuit has two modes including (1) an all-image display mode causingthe display to display all images transmitted from the plurality oftransmission terminals, and (2) an information display mode causing thedisplay to display the information transmitted from the transmissionmanagement apparatus, and the display control circuit switches betweenthe two modes when the operation input receiver receives the input, andtransmits the terminal information request to the transmissionmanagement apparatus after switching from the all-image display mode tothe information display mode.
 3. The first transmission terminalaccording to claim 1, further comprising an image data input unit towhich image data representing an image is input, wherein the displaycontrol circuit causes the display to display the image represented bythe image data that is input to the image data input unit of adesignated transmission terminal among the transmission terminals andtransmitted to the first transmission terminal, in addition to theinformation received by the receiver.
 4. The first transmission terminalaccording to claim 3, further comprising a sound data input unit towhich sound data is input, wherein the display control circuitidentifies the transmission terminal, from which the sound datarepresenting voices input to the sound data input unit is transmitted,as the designated transmission terminal among the plurality oftransmission terminals.
 5. The first transmission terminal according toclaim 2, further comprising an image data input unit to which image datarepresenting an image is input, wherein in the information display mode,the display control circuit causes the display to display the imagerepresented by the image data that is input to the image data input unitof a designated transmission terminal among the transmission terminalsand transmitted to the first transmission terminal, in addition to theinformation received by the receiver, and identifies one of thetransmission terminals as the designated transmission terminal when theoperation input receiver receives selection of a piece of information ofthe one of the transmission terminals from the information displayed onthe display.
 6. A transmission terminal control method using a firsttransmission terminal, comprising: transmitting, through a network, aterminal information request to a transmission management apparatus thatstores transmission states of a plurality of transmission terminals andpieces of information identifying the respective transmission terminalsso that the transmission states and the pieces of information areassociated with each other, the terminal information request indicatinga request for information for identifying at least a second transmissionterminal of the transmission terminals, the second transmission terminalbeing in communication with the first transmission terminal via asession established with the first transmission terminal; receiving,from the transmission management apparatus, a piece of informationidentifying the second transmission terminal that is acquired based onthe transmission state by the transmission management apparatus inresponse to the terminal information request; and causing a display todisplay a list including the piece of information identifying the secondtransmission terminal received in response to an input operation to thefirst transmission terminal.
 7. A computer program product comprising anon-transitory computer readable medium including programmedinstructions, wherein the instructions, when executed by a computerincluded in a first transmission terminal, cause the computer toexecute: transmitting, through a network, a terminal information requestto a transmission management apparatus that stores transmission statesof a plurality of transmission terminals and pieces of informationidentifying the respective transmission terminals so that thetransmission states and the pieces of information are associated witheach other, the terminal information request indicating a request forinformation for identifying at least a second transmission terminal ofthe transmission terminals, the second transmission terminal being incommunication with the first transmission terminal via a sessionestablished with the first transmission terminal, receiving, from thetransmission management apparatus, a piece of information identifyingthe second transmission terminal that is acquired based on thetransmission state by the transmission management apparatus in responseto the terminal information request; and causing a display to display alist including the piece of information identifying the secondtransmission terminal received in response to an input operation to thefirst transmission terminal.
 8. The first transmission terminalaccording to claim 1, wherein the piece of information identifying thesecond transmission terminal received by the receiver includes anidentifier of the second transmission terminal.
 9. The firsttransmission terminal according to claim 1, wherein the piece ofinformation identifying the second transmission terminal received by thereceiver includes name information related to the second transmissionterminal.
 10. The first transmission terminal according to claim 9,wherein the name information is related to the second transmissionterminal and obtained from the second transmission terminal.
 11. Thefirst transmission terminal according to claim 1, wherein the firsttransmission terminal is one of a video conference terminal, a carnavigation device, and a portable device.
 12. The first transmissionterminal according to claim 1, wherein the first transmission terminaland the second transmission terminal each transmit or receive contentdata via the session.
 13. The first transmission terminal according toclaim 12, wherein the content data includes at least image data.
 14. Themethod of claim 6, wherein the first transmission terminal has two modesincluding (1) an all-image display mode causing the display to displayall images transmitted from the plurality of transmission terminals, and(2) an information display mode causing the display to display theinformation transmitted from the transmission management apparatus, andthe causing step comprises switching between the two modes whenreceiving an input from a user, and transmitting the terminalinformation request to the transmission management apparatus afterswitching from the all-image display mode to the information displaymode.
 15. The method of claim 6, further comprising causing the displayto display an image represented by image data that is input to adesignated transmission terminal among the transmission terminals andtransmitted to the first transmission terminal, in addition to theinformation received in the receiving step.
 16. The method of claim 15,further comprising identifying the transmission terminal, from whichsound data representing voices input to a sound data input unit istransmitted, as the designated transmission terminal among the pluralityof transmission terminals.
 17. The method of claim 14, furthercomprising, in the information display mode, causing the display todisplay the image represented by the image data that is input to adesignated transmission terminal among the transmission terminals andtransmitted to the first transmission terminal, in addition to theinformation received in the receiving step, and identifying one of thetransmission terminals as the designated transmission terminal whenreceiving selection of a piece of information of the one of thetransmission terminals from the information displayed on the display.18. The method of claim 6, wherein the piece of information identifyingthe second transmission terminal includes an identifier of the secondtransmission terminal.
 19. The method of claim 6, wherein the piece ofinformation identifying the second transmission terminal includes nameinformation related to the second transmission terminal.
 20. The methodof claim 19, wherein the name information is related to the secondtransmission terminal and obtained from the second transmissionterminal.
 21. The method of claim 6, wherein the first transmissionterminal is one of a video conference terminal, a car navigation device,and a portable device.
 22. The method of claim 6, wherein the firsttransmission terminal and the second transmission terminal each transmitor receive content data via the session.
 23. The method of claim 22,wherein the content data includes at least image data.
 24. The computerprogram product of claim 7, wherein the piece of information identifyingthe second transmission terminal includes name information related tothe second transmission terminal.
 25. The computer program product ofclaim 24, wherein the name information is related to the secondtransmission terminal and obtained from the second transmissionterminal.